WASHINGTON (AP) — President Barack Obama voiced his conviction Tuesday night that Syrian President Bashar Assad was to blame for deadly chemical attacks against civilians, but again he offered no proof.

A look at his remarks to the nation, seeking support for a military strike against Syria, and how they compare with the facts as publicly known:

THE FACTS: The Obama administration has not laid out proof Assad was behind the attack.

The administration has cited satellite imagery and communications intercepts, backed by social media and intelligence reports from sources in Syria, as the basis for blaming the Assad government. But the only evidence the administration has made public is a collection of videos it has verified of the victims. The videos do not demonstrate who launched the attacks.

Administration officials have not shared the satellite imagery they say shows rockets and artillery fire leaving government-held areas and landing in 12 rebel-held neighborhoods outside Damascus where chemical attacks were reported. Nor have they shared transcripts of the Syrian officials allegedly warning units to ready gas masks or discussing how to handle U.N. investigators after it happened.

The White House has declined to explain where it came up with the figure of at least 1,429 dead, including 400 children — a figure far higher than estimates by nongovernmental agencies such as the British-based Syrian Observatory for Human Rights, which has counted only victims identified by name, with a current total of 502. In his remarks, Obama more generally accused Assad’s forces of gassing to death “over 1,000 people, including hundreds of children.”

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OBAMA: “So even though I possess the authority to order military strikes, I believed it was right in the absence of a direct or imminent threat to our security to take this debate to Congress.”

THE FACTS: Obama’s statement that he has the authority to launch military action is par for the course for presidents, and historically disputed by Congress. The issue never gets settled.

The Constitution delineates power between the president, who serves as commander in chief of the armed forces, and Congress, which has the ability to declare war. Over time, however, questions arose over where the president’s authority ends and where Congress’ begins.

The 1973 War Powers Resolution sought to end the debate, but it has only fueled arguments between Republican and Democratic administrations alike and those who consider themselves constitutional purists.

The law gives the president the power to act without congressional approval in cases of national emergency for up to 60 days. In such a case, the president must consult with Congress. And if the deadline passes without congressional authorization, the president has 30 additional days to remove troops.

But what constitutes a national emergency and what consultation means remain subjects of continued disputes.